Grinding device

ABSTRACT

The present invention relates to a grinding device in particular for the grinding of large-surface plates such as doors, shelves and table boards, but also of curved surfaces, and its purpose is to produce a grinding device that does not make the edges of the object to be ground round and in which the grinding paper, grinding cloth or the screen-like material can be replaced fast and easily, and the grinding dust of which is removed by means of suction so that the grinding material and the objects to be ground are cooled.

United States Patent [191 Franlinna [451 Aug. 28, 1973 GRINDING DEVICE {76] Inventor: Rauno Sakeri Franlinna, Minna Canthinkata 56A6, Kuopio, Finland [22] Filed: Sept. 23, 1971 [21] Appl. No.: 183,024

[51] Int. Cl B24b 7/12, B24b 55/06 [58] Field of Search 51/57, 59 R, 61, 51/62, 273

[56] References Cited UNITED STATES PATENTS 2,814,171 11/1957 Bogart 51/273 1,452,209 4/1923 Miller 51/273 2,012,555 8/1935 Walker 51/59 R Primary Examiner0thell M. Simpson Attorney-Fleit, Gipple & Jacobson 5 7] ABSTRACT The present invention relates to a grinding device in particular for the grinding of large-surface plates such as doors, shelves and table boards, but also of curved surfaces, and its purpose is to produce a grinding device that does not make the edges of the object to be ground round and in which the grinding paper, grinding cloth or the screen-like material can be replaced fast and easily, and the grinding dust of which is removed by means of suction so that the grinding material and the objects to be ground are cooled.

4 Claims, 7 Drawing Figures Patented Aug. 28, 1973 2 Sheets-Sheet l Patented Aug. 28, 1973 3,754,354

2 Sheets-Sheet 23 GRINDING DEVICE Board-like objects are oridinarily ground in grinding devices fitted with rotating grinding rollers. The opera tion and maintenance of such grinding devices involves several drawbacks, the worst of which are inconvenient replacing of the grinding papers or cloths and the heating up of the object to be ground and of the grinding papers. Moreover, devices of this type pollute the air of the working environment unless they are fitted with large and expensive dust-removing systems. By means of the device according to the present invention all of these disadvantages have been eliminated in a simple way, and its principal characteristics come out from the characteristic section of the attached patent claim I.

The invention is described in more detail below under reference to the attached drawings, which are only given as examples and in which FIG. 1 shows the grinding unit of the grinding device according to the invention as a side view,

FIG. 2 shows the punched grinding surface of the grinding unit according to FIG. I viewed from the top;

FIG. 3 shows a favourable arrangement of channels and dust grooves as a partial view,

FIG. 4 shows a preferable embodiment of FIG. 2 as viewed from the top,

FIG. 5 shows a partial lateral section of FIG. 4 in an enlarged scale,

FIG. 6 shows another favourable embodiment of the invention, and

FIG. 7 shows FIG. 6 as viewed from the top.

The grinding device according to the invention consists of a grinding unit that has been arranged so that it is located substantially horizontally. The grinding unit shown in FIG. 1 consists of a base plate I, to which a pyramide-shaped suction jacket 2 is fastened. The suction jacket is connected to a suction device by means of a tube 3 coupled to the bottom of the jacket, which tube is fitted with a flexible section. On top of the base plate I there is a slightly smaller even pad 4 of sponge rubber or equivalent. The base plate 1 and the soft pad 4 are fitted with through channels, as comes out from FIG. 2. Around the edges of the pad 4 ribs 5 are arranged to be fastened to the base plate,by means of which ribs the punched grinding paper or cloth or the screen-like material 6 spread over the pad 4 can be fastened. The punched grinding paper 6 is placed on the pad so that its holes are in alignment with the channels going through the base plate I and the pad 4.

The channels 7 in the grinding surface which go through the base plate I and the pad 4 are interconnected by means of dust grooves 8, which open against the non-grinding side of the grinding paper, cloth or the screen 6. FIG. 3 shows an advantageous channel-dust groove system of this type in which the channels 7 are interconnected by grooves 8 so that a symmetric figure is formed.

FIG. 4 shows another embodiment of the fastening of the grinding paper or cloth 6 to the grinding surface. On top of the base plate 1 several oblong soft pads 9 are arranged substantially perpendicularly against the feeding direction of the object to be ground, which direction is marked with A. The base plate 1 and the pads 9 are in this embodiment also fitted with channels 7 and dust grooves 3. Along the long side towards the feeding direction of the object to be ground of the pads 9 ribs 10 of the length of the pads are arranged to be fastened to the base plate, by means of which ribs the grinding papers, cloths or screens 6 are fastened. The punched grinding papers or cloths 6 are placed on top of the pads 9 so that their holes align with the channels 7 and so that the edge of the grinding papers or cloths 6 opposite to the long edge fastened by means of the ribs I0 is unfastened, as is shown in FIG. 4 regarding one pad 9.

The grinding unit is arranged so that it moves either to and fro or makes a circular or other suitable movement. Also, the plate to be ground may move alone as well as both the plate and the grinding unit may move. The plate to be ground may be pushed across the grinding surface perpendicularly to the toand-fro movement or in direction of the movement, but the former way has proved more advantageous. When the grinding surface is in agreement with FIG. 2, i.e. when one single grinding material is placed on top of the pad 4 and base plate 1 as fastened to the edges, it is possible, by means of the grinding device, to grind all the plane and curved surfaces that must be ground in carpentry, especially so if the grinding unit is made equally curved as compared with the object to be ground.

FIG. 6 is a side view of an embodiment of the invention in which there are two grinding units placed opposite each other. They are suspended on horizontal glide guides l l, and between the grinding units endless feeding chains 12 for the object to be ground have been arranged. The grinding units are interconnected by means of wires or chains 13 which run around the rollers 14. The lower grinding unit is at one edge by means of a rod 15 connected to a disc 16 eccentrically and the disc is rotated by an electrical motor 17. By this means the to-and-fro movement of the grinding units issimply achieved. FIG. 7 shows the grinding device of FIG. 6 viewed from the top.

The fastening of the grinding paper or cloth is done fast and easily by means of ribs in the grinding device according to the invention, but it is not always even necessary to fasten the grinding material, for its sticks to the pads 4 and/or base plate ll, because of suction, partly, and partly because of friction and/or burrs formed around the holes in connection with punching, for which reason the standing times of the machine remain quite short. The net-like sand screen elements can be placed on the pad or base plate as such, and in this case the grooves 8 may be entirely omitted. Onto the embodiment of grinding surface according to FIG. 4 it is possible to fasten several grinding papers, cloths or screens of different degrees of coarseness so that the coarseness is reduced in the direction of feeding, in which case the object can be ground by means of one single run.

Due to the quiet movement the grinding paper or cloth remains smooth and is not torn or blocked. Due to the strong suction the loose grinding dust escapes through the suction channels while the air at the same time cools the grinding paper and the surface of the object to be ground. Due to the flexible sponge rubber pads even the finest surfaces of plywood with precious wood lining etc. may be ground without the corners being ground through.

Another major advantage of the device is that it keeps the air of the working environment dust-free.

The invention is not restricted to the above embodiments which are only described by way of example, but

can be modified within the range of the attached patent claims in many different ways, for example so that it is used for hard-waxing and polishing.

What I claim is:

l. A grinding machine for grinding articles comprising a jacket having wall means defining an opening therein, a base plate mounted over said opening in said jacket, pad means mounted on said base plate and partly covering said base plate, grinding means arranged on said pad means and having a larger area than said pad means, means securing said means to said base plate, said base plate and pad means having walls means defining a plurality of channels extending through said base plate and said pad means, each channel in said base plate being in line with a corresponding that particles removed from an article being ground are caused to be drawn through said apertures in said grinding means and said channels of said pad means and base plate and into said jacket.

2. A grinding machine according to claim 1, wherein said paid means comprising a plurality of spaced elongated pads positioned transversely to the direction of grinding movement and each carrying a grinding means.

3. A grinding machine according to claim 2, wherein each said grinding means is fastened by means of fastening ribs to said base plate only along the pad edges facing the direction of feeding of said article to be ground.

4. A grinding machine according to claim 1, and further comprising wall means defining a plurality of grooves situated on the surface of said pad means and facing said grinding means and connecting each of said channels with adjacent channels.

Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N 3.754 354 Dated Auqust 28. 1973 Inventor s) RAUNO SA KARI ERANLINNA It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The last name of the inventor should be corrected throughout the patent to read ERANLINNA Signed and sealed this 11th day of June 19714..

(SEAL) Attest:

EDWARD M.FLETcEER; JR. 0 MARSHALL DANN Commissioner of Patents RM P0405? (0459) USCOMM-DC moan-Pea fl U.5 GOVERNMENT PRINTING OFFICE 9.9 0-3893)" 

1. A grinding machine for grinding articles comprising a jacket havinG wall means defining an opening therein, a base plate mounted over said opening in said jacket, pad means mounted on said base plate and partly covering said base plate, grinding means arranged on said pad means and having a larger area than said pad means, means securing said means to said base plate, said base plate and pad means having walls means defining a plurality of channels extending through said base plate and said pad means, each channel in said base plate being in line with a corresponding channel in said pad means, said grinding means including punched portions, said portions defining apertures being in line with said channels and providing burrs projecting into said channels in said pad means thereby securing said grinding means to said pad means, and means for creating a low pressure within said jacket so that particles removed from an article being ground are caused to be drawn through said apertures in said grinding means and said channels of said pad means and base plate and into said jacket.
 2. A grinding machine according to claim 1, wherein said paid means comprising a plurality of spaced elongated pads positioned transversely to the direction of grinding movement and each carrying a grinding means.
 3. A grinding machine according to claim 2, wherein each said grinding means is fastened by means of fastening ribs to said base plate only along the pad edges facing the direction of feeding of said article to be ground.
 4. A grinding machine according to claim 1, and further comprising wall means defining a plurality of grooves situated on the surface of said pad means and facing said grinding means and connecting each of said channels with adjacent channels. 